In an older PR a reviewer had asked why the discarding of a channel
being blocked on another monitor update is okay if the blocked
channel has since closed. At the time, this was not actually okay -
the monitor updates in the channel weren't moved to the
`ChannelManager` on close so the whole pipeline was busted, but
with the changes in 4041f0899f the
handling of channel closes with pending monitor updates is now
correct, and so is the existing code block.
If a `ChannelMonitorUpdate` completes being persisted, but the
`ChannelManager` isn't informed thereof (or isn't persisted) before
shutdown, on startup we may still have it listed as in-flight. When
we compare the available `ChannelMonitor` with the in-flight set,
we'll notice it completed and remove it, however this may leave
some post-update actions dangling which need to complete.
Here we handle this with a new `BackgroundEvent` indicating we need
to handle any post-update action(s) for a given channel.
If a channel has been closed, there may still be some
`ChannelMonitorUpdate`(s) which are pending completion. These
in-flight updates may also be blocking another channel from letting
an update fly, e.g. for forwarded payments where the payment
preimage will be removed from the downstream channel after the
upstream channel has closed.
Luckily all the infrastructure to handle this case is already in
place - we just need to process the
`monitor_update_blocked_actions` for closed channels.
This was a regression resulting from f2453b7 since we now process events
in a loop until there aren't any left. Processing events is done in
batches and they are not removed until we're done processing each batch.
Since handling a `PendingHTLCsForwardable` event will call back into the
`ChannelManager`, we'll still see the original forwarding event not
removed. Phantom payments will need an additional forwarding event
before being claimed to make them look real by taking more time.
Because `ChannelMonitorUpdate`s can complete asynchronously and
out-of-order now, a `commitment_signed` `ChannelMonitorUpdate` from
a downstream channel could complete prior to the preimage
`ChannelMonitorUpdate` on the upstream channel. In that case, we may
not get a `update_fulfill_htlc` replay on startup. Thus, we have to
ensure any payment preimages contained in that downstream update are
re-claimed on startup.
Here we do this during the existing walk of the `ChannelMonitor`
preimages for closed channels.
* `PhantomRouteHints::channels` has been written since the struct
was added in 410eb05365.
* `HTLCSource::path_hops` has been written since the struct was
converted to TLVs in 66784e32fe.
This commit makes use of the added enum to calculate the dust
exposure threshold based on the current fee rate. This also updates
tests to ensure it works as intended.
This ensures freshly initialized nodes can proceed to create unexpired
invoices without a call to `best_block_updated`, since an invoice's
expiration delta is applied to `highest_seen_timestamp`.
Since the use of channels with anchor outputs requires a reserve of
onchain funds to handle channel force closures, it would be
irresponsible to allow a node to accept inbound channel without first
consulting such reserves. To allow users to do so, we require such
channels be manually accepted.
Now that all of the core functionality for anchor outputs has landed,
we're ready to remove the config flag that was temporarily hiding it
from our API.
`Channel::get_latest_complete_monitor_update_id` no longer refers
to complete updates, but rather ones which were passed to the
`ChannelManager` and which the `CHannel` no longer knows about.
Thus, we rename it `get_latest_unblocked_monitor_update_id`.
Because `ChannelMonitorUpdate`s can be generated for a
channel which is already closed, and must still be tracked
through their completion, storing them in a `Channel`
doesn't make sense - we'd have to have a redundant place to
put them post-closure and handle both storage locations
equivalently.
Instead, here, we move to storing in-flight
`ChannelMonitorUpdate`s to the `ChannelManager`, leaving
blocked `ChannelMonitorUpdate`s in the `Channel` as they
were.
By giving up on a tiny bit of parallelism and tweaking the return
types, we can make the `handle_new_monitor_update` macro a bit
clearer - now the only cases where its called after a monitor was
updated was when the monitor was initially committed.
Most of the calls to the `handle_new_monitor_update` macro had the
exact same pattern - calling `update_monitor` followed by the
macro. Given that common pattern will grow to first pushing the
new monitor onto an in-flight set and then calling `update_monitor`
unifying the pattern into a single macro now avoids more code churn
in the coming commits.
In the coming commits we'll move to storing in-flight
`ChannelMonitorUpdate`s in the `ChannelManager` rather in the
`Channel` (which will then only retain `ChannelMonitorUpdate`s
which have not yet been released/are blocked.
This will simplify handling of pending `ChannelMonitorUpdate` after
a channel has closed by not having to move them into the
`ChannelManager`.
Downstream crates building fur fuzzing will usually set
`--cfg=fuzzing` as a side-effect of the Rust fuzzing tooling. Thus,
we should ensure we build without failure in such cases.
We do this here by simply relying on the `_test_utils` feature,
rather than conditionally-compiling in modules based on the
`fuzzing` flag.
Make sure the penultimate hop took the amount of fee that they claimed to take.
Without checking this TLV, we're heavily relying on the receiving wallet code
to correctly implement logic to calculate that that the fee is as expected.
Useful for penultimate hops in routes to take an extra fee, if for example they
opened a JIT channel to the payee and want them to help bear the channel open
cost.
We need the channel lock for constructing a pending HTLC's status because we
need to know if the channel accepts underpaying HTLCs in upcoming commits.
This commit also adds two new maps to `PeerState` for keeping track
of `OutboundV1Channel`s and `InboundV1Channel`s so that further
commits are a bit easier to review.
